In: Economics
1. Given the following system equations of price (P) and quantity (Q) determination in a widget market:
SHOW ALL WORK!
Demand: Q = 100 - 4P + 2G …..(1)
Supply: Q= 60 + 10P – 3N ……(2)
Where the price of substitute good, G = 10, and the cost of production N = 8.
1-a) by using the repeated substitution method only, please find equilibrium P and Q.
1-b) if G is up by 2, shows the impact of changing N on P and Q.
Given that:
Demand: Q = 100 - 4P + 2G -- equation 1)
Supply: Q = 60 + 10P – 3N -- equation 2)
If G = 10, and N = 8
1-a) Solution
Equilibrium will occur when:
D = S
Thus, equating 1) and 2)
100 - 4P + 2(10) = 60 + 10P – 3(8)
100 - 4P + 20 = 60 + 10P - 24
120 - 4P = 36 + 10P
120 - 36 = 14P
84 = 14P
P = $6
To find Q, substitute the value of P in equation 1)
Q = 100 - (4 x 6) + (2 x 10)
Q = 100 - 24 + 20
Q = 96 units
We may also verify the same by substituting P in equation 2)
Q = 60 + 10P - 3N
Q = 60 + (10 x 6) - (3 x 8)
Q = 120 - 24
Q = 96 units
Hence, equilibrium Price is $6, and Quantity is 96 units
1-b) If G is up by 2, the equilibrium P and Q will change as follows.
N will not change in this case. No information is provided on change in N.
The new value of G is now 12.
Equilibrium will occur when:
D = S
Thus, equating 1) and 2)
100 - 4P + 2(12) = 60 + 10P – 3(8)
100 - 4P + 24 = 60 + 10P - 24
124 - 4P = 36 + 10P
124 - 36 = 14P
88 = 14P
P = $6.286
To find Q, substitute the value of P in equation 1)
Q = 100 - (4 x 6.286) + (2 x 12)
Q = 100 - 25.144 + 24
Q = 98.86 ~ 99 units
We may also verify the same by substituting P in equation 2)
Q = 60 + 10P - 3N
Q = 60 + (10 x 6.286) - (3 x 8)
Q = 122.86 - 24
Q = 98.86 ~ 99 units
Hence, new equilibrium Price is $6.286, and Quantity is 99 units.
Due to the increase in price of substitute good, the quantity demanded of widgets will rise. This will cause a rise in the price of widgets. Sellers will also now be able to sell more widgets.